Level conversion circuits (also known as level shifters) are useful in integrated circuits for converting between signals in different voltage domains having different upper/lower voltage levels. In some cases it is required to provide a level conversion circuit which can switch both from a domain having a smaller upper voltage to a domain having a larger upper voltage, and from a domain having a larger upper voltage to a domain having a smaller upper voltage. Existing integrated circuit level conversion circuits of this type have a problem in that they either the incur increased power consumption because they have a direct leakage path between higher and lower power rails, or they have additional circuitry for addressing this leakage problem, but at the cost of an additional delay. The delay means that the output signal of the level conversion circuit responds slowly to changes in the input signal, which is a problem for high performance circuits.
The present technique seeks to address these problems and provide a level conversion circuit which can provide level conversion both from low-to-high and from high-to-low, and which provides improved performance and power efficiency compared to previous circuits.